This article was first published in The Structural Engineer on 2 February 2026.

With a proactive approach and early engagement,structural engineers can unlock the reuse potential of existing buildings and steer the industry away from demolition, explains Thomas Hesslenberg.

As reuse-first planning policies gain momentum, structural engineers have a unique position to help influence planning and client decisions on reuse. This influence can increase the reuse of existing buildings, but only if structural engineers are involved early and are confident in demonstrating the potential that reuse has to bring.

In recent years, the Greater London Authority (GLA), a few London boroughs and a handful of local authorities across the country have updated their local plans and Sustainability Planning Documents (SPDs), with stricter requirements being introduced for the assessment of existing buildings, along with the reuse and retrofitting potential that needs to be explored. Furthermore, the National Planning Policy Framework (NPPF) is looking to add further passages within the climate change and embodied carbon section to give ‘substantial weight’ to the reuse of existing buildings this year. These assessments often take the form of Pre-Redevelopment Audits and Pre-Demolition Audits, the latter requiring design teams to quantify the materials that would be proposed to be removed from buildings through demolition.

These audits are generally welcomed, as they help authorities and design teams understand redevelopment potential and the materials likely to be removed. However, they are often undertaken to a minimal standard, aimed at satisfying planning requirements rather than informing decision-making. Without early structural engineering input, audits can rely on inaccurate data and limited assumptions, leading to missed reuse opportunities and reduced client confidence in retrofit-led solutions.

To add value, structural engineers should be engaged early on as part of the Pre-Redevelopment Audit stage. At present, these audits mainly apply to GLA Major Applications and/or a small number of London boroughs, including  Westminster, the City of London and Camden. The suggested hierarchy poses questions such as:

• Is it technically feasible to retain the building in whole or part?
• Is the existing building, or parts of it, suited to the requirements of the site?
• What condition is the existing building in?

The London Borough of Westminster has recently set the bar high, by introducing the Westminster Retrofit First Policy. Under this policy, proposals involving substantial demolition, defined as more than 50% of the GIA, must pass a series of Sequential Tests, which go beyond the steps of a Pre-Redevelopment Audit. These tests must show that demolition and new build are the only viable option in order to get planning approval for substantial demolition. These tests require structural engineering input and when given the appropriate attention, provide the most comprehensive arguments. While some developers may view this as a barrier to new development, it presents an opportunity for structural engineers and allows them to demonstrate value earlier and help shape the client’s brief from the outset.

To achieve this earlier involvement, structural engineers must take a proactive approach. The aim should be to improve reuse outcomes by understanding local planning requirements, working closely with project teams and demonstrating how early structural input can unlock reuse potential. Early engagement can identify opportunities to retain and adapt existing structures, avoid unnecessary demolition and reduce abortive design work. This helps to de-risk projects while maximising the value of existing assets.

As planning policy increasingly prioritises reuse, the success of this shift will depend on early, confident structural engineering input. Structural engineers are uniquely placed to assess what existing buildings can realistically accommodate, to challenge assumptions around demolition, and to give clients and design teams the technical and commercial confidence needed to pursue retrofit-led solutions. While not every building will be suitable for reuse, these decisions must be informed by robust structural understanding rather than default positions or late-stage assessments. By engaging earlier in the planning process, embracing reuse-first policies, and sharing knowledge across the profession through such initiatives as The Engineers Reuse Collective, structural engineers can help make retrofit a credible, deliverable, and mainstream outcome—transforming reuse from an exception into a normal part of development decision-making.

Thomas Hesslenberg is an Associate at Elliott Wood and a Steering Group member of The Engineers Reuse Collective.